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Heat A Form of Energy.

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Presentation on theme: "Heat A Form of Energy."— Presentation transcript:

1 Heat A Form of Energy

2 Molecules and Motion The motion of molecules produces heat The more motion, the more heat is generated

3 Heat Transfer The movement of heat from warmer object to colder one Heat moves ‘downhill’ from ‘High to Low’

4 Heat Transfer~Thermodynamics
Three forms of heat transfer (movement): Conduction Convection Radiation

5 Conduction transfer of heat through direct contact, has to TOUCH!!
Heat conductors “carry” heat Insulators “protect” from heat movement Conduction

6 H Convection C Takes place in liquids and gases as molecules move in currents Hotter rises and cooler sinks Currents cause winds which move heat energy around Earth’s atmosphere

7 RADIATION (radiant energy)
Transfers heat through space Energy from the sun being transferred to the Earth

8 Questions What are the three types of heat transfer? How is conduction different from radiation?

9 What type of heat transfer is involved?
Heating a room with a fireplace Egg cooking in a frying pan Roof of a house becoming hot

10 What type of heat transfer?
Warm air mass bringing a change in the weather Wire getting hot from an electric appliance

11 Temperature and Heat Kinetic energy is the energy of motion Temperature is the measure of the average kinetic energy of an object

12 Question How is kinetic energy related to heat production?

13 Thermometer A instrument used to measure temperature
Thermometers commonly have alcohol (with dye) or mercury Digital thermometers have replaced older ones

14 Celsius Scale Celsius is the metric scale for measuring temperature Water freezes at 0ºC and boils at 100ºC

15 Kelvin scale The Kelvin scale is a metric temperature scale measured in Kelvin units (K) Formula (273+ºC)= Kelvin

16 Questions What is the formula for converting a Celsius temperature to a Kelvin temperature? What is the boiling point of water on the Kelvin scale? What is the freezing point of water on the Kelvin scale?

17 Absolute zero The temperature in which all molecular motion stops (0ºK) The 5th phase of matter occurs at 0ºK—Einstein-Bose state

18 Questions Describe absolute zero. What is absolute zero on the Celsius scale?

19 Measuring Heat Increase in temperature Addition of heat
Decrease in temperature Removal of heat

20 Temperature Joule is another unit for measuring heat
Mass and type of substance determine the amount of temperature change

21 Questions How can heat be measured? What is the unit used to measure heat?

22 Heat & Phase Changes SolidLiquid, LiquidSolid LiquidGas, GasLiquid
A phase change is a physical change that requires a change in heat energy Addition or removal of HEAT SolidLiquid, LiquidSolid LiquidGas, GasLiquid SolidGas, GasSolid

23 Questions What are: freezing point, melting point, and boiling point?

24 Heat expansion The increase in volume of a substance due to heat
Most solids, liquids, and gases expand as they are heated Between 4ºC and 0ºC, water EXPANDS as it cools and turns into a solid, which “traps” air in the ice—so ice floats

25 Video Links Review Study Jams Video

26 Video Links Review BBC Video

27 Video Links Summary Khan Academy


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